Hello,
(still struggling with the mailing list, hope this one is sent properly)

> Do any other distributions offer such indications of the number of
users of a package? Fedora, Gentoo, Arch, Ubuntu?

As for the distribution on the Snap Store[1], the exact metrics are only
available to the publisher and its collaborators(I would love to give
you access, unfortunately it requires an Ubuntu One account[2]).

* 44 weekly active devices[4], including 35 tracking the stable
channel(3.2) and 9 tracking beta and edge channel(currently 3.2-42-g55537dc)
Note that the systems that uninstall the snap afterwards and the ones
that not become online in a week period will be deducted from this number.

* People in 22 territories[5] has installed the snap, the top three:
* United States(9)
* Germany(5)
* Canada(4)

* 24 of the snap users are using nano on Ubuntu Core[6] devices, perhaps
nano isn't shipped by default...? :-/

That's all for now, I'll post an update about the current status of the
nano snap in the next few days.